Typically in the prior art a loudspeaker resides in a housing. For protective and aesthetic reasons a cover is placed over the radiating face of the loudspeaker concealing the loudspeaker's components. The cover must allow sound to pass unimpeded while simultaneously serving the protective and aesthetic functions of loudspeaker covers. These porous covers can be made of cloth or other porous material.
In the past, loudspeaker covers have been passive devices. Some as in U.S. Pat. Nos. 6,142,254, and 5,717,171, describe enhanced aesthetic covers for loudspeakers.
In the Entertainment Lighting field, many patents, such as U.S. Pat. Nos. 4,000,679, and 4,265,159 describe entertainment lighting devices which actively respond to sound waves. Amplitudes of the sound waves are often used to turn lights on and off as well as to adjust brightness. Relative frequency and/or time sequencing is often used to operate different colored lights. These devices are not integral with loudspeakers.
Many devices which are used to tune stringed instruments are known in the art and are capable of determining the dominant frequency of an electrical signal from a musical instrument. U.S. Pat. No. 4,151,775 discloses such a device. These devices were not intended for entertainment lighting.